Tire Pressure

[ByrdDog20]

Just got a (new) 2000 Taco 4x4 V6 auto, came with BF Goodrich All Terrain TA KO 32-11.5-15 tires on stock rims.

Since all four tires are different pressures right now, what tire pressure for driving on mostly freeway?

Also, these tires are new, bought November 3 from Discount Tire, anyone interested in buying or trading for more stock (31x10.5 or 255/70) size tires of similar age?

Thanks

[YoTRacer158]

i ran my 32x11.5 AT's at 32psi

[seth_js]

What about 285/75-16? What's a good pressure for street? Trails?

[hytenor]

there is no set psi for all applications. different tires, brands of tire, sizes, etc. will require different psi. front and rear will be different; different trucks, reg, ex, dcab, with/without camper shell, etc, etc, etc.....

so, get used to doing the 'chalk test'.

get some chalk. color an area in front of each tire on the street, wide enough to catch the entire width of the tire and about 12" long. drive over them. look at the amount of chalk that each tire has taken up. you are looking for an even 'patch' across the width of the tire and about the same length (as the width). If you tire is under inflated the centers will be light or bare of clalk. If the tires are over inflated the edges will be light. Adjust the air pressure until you get a nice even 'patch'.

make sense?

the idea is to run the highest psi possible that maintains an even contact patch.

when you carry heavy loads the psi will have to be adjusted.

[ByrdDog20]

I like the chalk idea. I suppose I have to do two seperate patches, one for the front tires, one for the rear due to the different weight on each axle.

[YoTRacer158]

you do a patch in front of each tire....both front and both rear. you can also draw lines across the tire itself to measure wear that way too

[hytenor]

Originally Posted by YoTRacer158

you do a patch in front of each tire....both front and both rear. you can also draw lines across the tire itself to measure wear that way too

good point and quicker than my idea as long as the line is solid from edge to edge the rest of the 'patch' should be fine as well. I've used a little water in the past as well.

[hytenor]

Originally Posted by ByrdDog20

I like the chalk idea. I suppose I have to do two seperate patches, one for the front tires, one for the rear due to the different weight on each axle.

yup, when unloaded I run 30f/26r with my 33x10.50 BFG Mts.

[ibidu1]

Another anal thing to make sure when checking air psi, always measure them with cold tires. The hotter the tire the more psi it will show.

[alex9021]

Originally Posted by hytenor

there is no set psi for all applications. different tires, brands of tire, sizes, etc. will require different psi. front and rear will be different; different trucks, reg, ex, dcab, with/without camper shell, etc, etc, etc.....

so, get used to doing the 'chalk test'.

get some chalk. color an area in front of each tire on the street, wide enough to catch the entire width of the tire and about 12" long. drive over them. look at the amount of chalk that each tire has taken up. you are looking for an even 'patch' across the width of the tire and about the same length (as the width). If you tire is under inflated the centers will be light or bare of clalk. If the tires are over inflated the edges will be light. Adjust the air pressure until you get a nice even 'patch'.

make sense?

the idea is to run the highest psi possible that maintains an even contact patch.

when you carry heavy loads the psi will have to be adjusted.

Do you increase or decrease the PSI when you carry heavier load?

[YoTRacer158]

Originally Posted by ibidu1

Another anal thing to make sure when checking air psi, always measure them with cold tires. The hotter the tire the more psi it will show.

yeah but wouldnt you want to check them at operating temp?

[flatlandtacoma]

Originally Posted by alex9021

Do you increase or decrease the PSI when you carry heavier load?

You add air to the tires for a loaded truck.

[alex9021]

Originally Posted by flatlandtacoma

You add air to the tires for a loaded truck.

So you're saying that if I do a chalk test and come up with 32 PSI as the "correct" pressure for my tire, I will have to do more than 32 PSI when the truck is loaded.

[YoTRacer158]

Originally Posted by alex9021

So you're saying that if I do a chalk test and come up with 32 PSI as the "correct" pressure for my tire, I will have to do more than 32 PSI when the truck is loaded.

correct...the weight will cause the tire to flatten out, like being underinflated

[ibidu1]

Originally Posted by YoTRacer158

yeah but wouldnt you want to check them at operating temp?

No, you want to set the right temp when tires are cold. Those stick tire checkers are garbage, you should use a nice digital meter.

I race bikes and tire psi is very critical for us.

[hytenor]

Originally Posted by alex9021

Do you increase or decrease the PSI when you carry heavier load?

answered by others...

I max out the rears at 50 with a full load of firewood and run the fronts at 40 or so. Otherwise the ride is scary at best, LOL